High-absorbency materials may be organic or inorganic, and can include, for example, clays, pectin, peat moss, carboxymethylcellulose, hydrophilic polymers and mixtures thereof. Such materials have been included into fibrous absorbent bodies to increase the absorbent capacity. The absorbent bodies have then been incorporated into various articles, such as bandages, diapers, feminine sanitary pads, incontinence garments, and the like.
Typically, the absorbent body is composed of cellulose wadding or cellulosic wood pulp material commonly referred to as "fluff". An absorbent body composed of wood pulp fluff is typically formed by employing conventional airlaying techniques, such as those shown in U.S. Pat. No. 4,388,056 issued June 14, 1983 to F. Lee, et al. and U.S. Pat. No. 3,973,291 issued Aug. 10, 1976 to C. Kolbach.
The high-absorbency material has been incorporated into the absorbent body employing various arrangements. For example, the high-absorbency material has been confined to selected layers or pockets within the absorbent body, as representatively shown in U.S. Pat. No. 1,702,530 issued Feb. 19, 1929 to H. Williams and U.S. Pat. No. 4,333,462 issued June 8, 1982 to D. Holtman, et al. The high-absorbency material has also been configured as particles distributed into an absorbent body, as shown in U.S. Pat. No. 3,670,731 issued June 20, 1972 to C. Harmon. Other absorbent body configurations have restricted the high-absorbency material to a rectilinear, central zone of the absorbent body, thereby leaving lateral zones that are free of the high-absorbency material. For example, see U.S. Pat. No. 3,888,257 issued June 10, 1975 to R. Cook, et al. Still other configurations have restricted the high-absorbency material to the lateral zones of the absorbent body, as representatively shown in U.S. Pat. No. 4,212,302 issued July 15, 1980 to H. Karami.
To distribute and locate the high-absorbency material within the absorbent body, various techniques have been employed. For example, the high-absorbency material has been secured to a carrier layer or web which is then assembled into the absorbent body. A typical configuration is shown in European patent application EP 0 160 572 A2 published Nov. 6, 1985 with the inventors listed as E. Erdman, et al. Particles of high-absorbency material have also been deposited onto a fluff pad and distributed into the voids between the absorbent fibers employing high velocity air to inject particles into the fluff pad. For example, see U.S. Pat. No. 4,087,506 issued May 2, 1978 to R. Cook, et al. Still other devices, such as the apparatus described in U.S. Pat. No. 3,262,423 issued July 26, 1966 to W. Willhite, have been employed to uniformly deposit a particulate material onto a moving porous web.
Conventional devices and techniques, such as those discussed above, have not, however, been sufficiently capable of efficiently producing an absorbent body having high-absorbency material distributed in selected concentration distributions or gradients through the thickness dimension or across the width dimension of the absorbent body. In addition, the conventional forming techniques have not been sufficiently able to deliver high-absorbency materials in a substantially uniformly dispersed configuration that can be readily directed and distributed into predetermined locations and patterns within the absorbent body. As a result, articles, such as disposable diapers, feminine sanitary napkins, incontinence garments and the like, have not been able to efficiently incorporate desired distribution patterns of components to more effectively use the absorbent capacities of the high-absorbency material.